The present invention relates to testing of a hazardous gas detector and more particularly, to testing of a hazardous gas detector in fluid communication with ductwork without removal of a cover enclosing the hazardous gas detector.
The use of hazardous gas detectors is common within homes, offices and other buildings for the purpose of sounding an alarm upon the onset of a fire or other asphyxiation danger within the building. Hazardous gas detectors regardless of whether operating on ionization or optical absorption principles trigger an alarm upon sensing a threshold quantity of smoke particulate or hazardous gas so as to give people within the building early notification of the existence of a danger. While smoke detectors are frequently mounted in ceilings and other elevated regions within building rooms to take advantage of the fact that smoke rises to enhance the sensitivity of the smoke detector in residential buildings and other heavier than air hazardous gas detectors are situated proximal to combustion equipment, in commercial buildings and manufacturing facilities, hazardous gas detectors are most often coupled to air handling conduits. The air handling ducts of commercial or manufacturing facilities force air through a hazardous gas detector coupled to the air handling ductwork thereby reducing the number of hazardous gas detectors necessary to provide warning within a large structure and also to further enhance the sensitivity of the hazardous gas detector by actively forcing air therethrough.
Hazardous gas detectors coupled to forced air ductwork are encased within a cover enclosing the hazardous gas detector and often power leads thereto to lessen ductwork pressure drop across the hazardous gas detector. Since hazardous gas detectors function under operating conditions for extended periods of time without encountering threshold quantities of hazardous gas capable of triggering an alarm, it becomes necessary to test the operating condition of the hazardous gas detector at regular intervals. While the testing of a home smoke detector by bringing a fire source such as a lit match or candle or aerosol smoke into proximity with the smoke detector is a minor inconvenience, the testing of hazardous gas detectors coupled to ductwork becomes quite burdensome. In many cases, hazardous gas detectors coupled to ductwork are in inaccessible regions of a commercial or manufacturing facility. Further, testing of a ductwork coupled hazardous gas detector entails removal of the cover therefrom often through the removal of several fasteners. As a result, periodic testing of ductwork coupled hazardous gas detectors in a commercial or manufacturing facility can require several hours of hazardous work involving climbing a ladder or utilizing crawl spaces to access hazardous gas detector covers and often high-voltage power terminals. Thus, there exists a need for a duct coupled hazardous gas detector cover which is accessible for the testing of a hazardous gas detector enclosed therein without the necessity of removing the cover.
A confined gas stream coupled to a hazardous gas detector enclosure includes a housing and a cover such that the housing and cover together define a volume adapted to enclose a hazardous gas detector. An aperture extends through either the housing or the cover. A port test valve is adapted to seat within the aperture.
A system for testing a confined gas stream coupled hazardous gas detector includes a hazardous gas detector in fluid communication with an inlet duct and an outlet duct. A housing and a cover together define a housing volume adapted to enclose the detector. An aperture is located in at least one of the housing and the cover. A port test valve is adapted to seat within the aperture and is matable to a nozzle delivering a hazardous gas test mixture into the housing volume in sufficient quantity to elicit an active alarm signal from the gas detector. A process for testing a confined gas stream coupled hazardous gas detector includes sealing the detector within a volume and exposing the detector to the confined gas stream and thereafter introducing into the gas stream a quantity of hazardous gas test mixture through a port test valve to trigger an active alarm signal in the detector.